That threshold of six counts ensured that James G. Madison, 50, would be considered for the harshest penalty: as many as 20 years in prison for each count. Additional bank robbery counts would not bring more prison time.

U.S. Attorney Christopher J. Christie said that sentencing guidelines suggest a term of about nine years for Madison, but that prosecutors would seek a sentence of about 11 years. Unlike state terms, there is no parole eligibility with federal sentences.

Madison's plea came two weeks after he surprised courtroom spectators by scrapping a plea bargain and asserting his innocence.

The machinist's balding head had been covered by a succession of hats, earning him the nicknames "Mad Hatter" and "Hat Bandit." The robberies netted $60,000 after notes were passed to bank tellers, authorities said.

U.S. District Judge Jose L. Linares scheduled a Dec. 18 sentencing hearing.

Madison, of Maplewood, has been held without bail since his arrest July 23, one day after the robbery of a bank in Union Township that authorities said led to the break in the case. A bank employee wrote down the license number of a car used in the heist, and police traced it to a woman who lives with Madison.

Madison had been imprisoned for nearly two decades after being convicted of manslaughter in the January 1986 death of a girlfriend, Terry Wells. Her body was found in a suitcase in the Passaic River.